Motor vehicle transmission with means to prevent differential rotation of wheels



Julyv 13, 1965 T. D. PARKS 3,194,337

MOTOR VEHICLE TRANSMISSION WITH MEANS TO PREVENT DIFFERENTIAL ROTATIONOF WHEELS Filed Oct. 23, 1963 2 Sheets-$heet 1 y 13, 1965 T. D. PARKS3,194,337

MOTOR VEHICLE TRANSMISSION WITH MEANS 1'0 PREVENT DIFFERENTIAL ROTATION0F WHEELS FiledOct. 23, 1965 2 Sheets-Sheet 2 I6 I n FIG-4 5 6 9 UnitedStates Patent 0 Iaml The invention relates to motor vehicle transmissionsystems.

Under normal ground conditions, a pair of wheels driven by the enginethrough a differential gea drive, will drivingly engage the ground andthe vehicle will move; but where ground conditions are such that one orboth of the wheels of the pair slip, the vehicle may be unable to move.An object of the invention is to provide means whereby this disadvantagewill be overcome.

According to the invention there is provided in or for a motor vehiclehaving a pair of laterally-spaced wheels arranged to be'driven through adifferential gear drive positionedbetween them, an additional drivemechanism movable into or out of an operative position in which itpositively'couples one of the wheels of the pair to the other.

Preferably, the additional drive mechanism comprises a pair oflaterally-spaced rollers positioned one at each side of the chassis forrotation about a common axis parallel with the common axis of the wheelsand intercom nected by shaft means to be supported from the chassis, therollers being movable into and out of positions in which they will eachengage a peripheral portion of the adjacent wheel of the said pair,thereby to effect a direct drive, through the rollers and the shaftmeans, from one to the other of the pair of wheels.

Each roller may 'be movable into and out of a position in which it isengageable with the peripheral face of the tyre of the respective wheel.

The rollers may be mounted on and rotatable with a shaft, arranged toextend transversely across the chassis and carried on arms or linksarranged to be pivotally mounted on the chassis, whereby the rollers andthe shaft are bodily movable, by swinging the arms or links about theirpivots, into and out of the position in which the rollers engage therespective wheels.

By way of example, one form of the invention will now be described withreference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of the driven wheels and part of thechassis of a motor vehicle fitted with an additional drive mechanism inaccordance with this invention, the said mechanism being shown in theoperative position;

FIGURE 2 is a side view to a larger scale and part in section of themechanism shown in FIGURE 1, the wheels of the vehicle having beenomitted;

FIGURE 3 *i's'an end view in the direction of arrow III in FIGURE 2of aportion of the mechanism at one side only of the vehicle, and

FIGURE 4 is a plan view in the direction of arrow IV in FIGURE 2 of aportion of the mechanism at one side only of the vehicle.

The additional drive mechanism comprises a shaft 1 extendingtransversely beneath the chassis 2 of the vehicle and carnied in a pairof laterally-spaced bearing blocks 3 suspended from the chassis. Theshaft 1 is located from axial movement in the bearing blocks by means ofa pair of collars 4, each positioned adjacent the inside face of theadjacent bearing block 3, one in the position shown in FIGURE 3 and theother in a corresponding position adjacent the other end of the shaft.Each bear- "ice ing block 3 is suspended from one or other side of thechassis by a pair of links, each pivotally connected at the lower endthereof to the respective bearing block and at the other end thereof tothe chassis. One of the links at each side of the chassis is adjustablein length and comprises an internally screwed sleeve 5, which is engagedat each end with the screwed end of a pair of U-shaped shackles 6 and 7in the manner of a turnbuckle. The threads at each end of the sleeve 5are of opposite hands so that as the sleeve is turned by means of bars 8extending radially from the sleeve 5, the distance between the shackles6 and 7 can be varied. To facilitate rotation of the sleeve, the screwthreads are of truncated form, e.g. Acme threads. At each side of thevehicle the upper shackle 6 is pivotally connected by a bolt 9 to aplate 10, bolted to the chassis, and the lower shack-1e 7 is pivotallyconnected by a bolt 11 to a tongle 12 on the bearing block 3. The otherlink at each side of the vehicle is a simple strap 14 of fixed lengthpivotally connected at its lower end between spaced jaws 15 on the"bearing block 3 by a bolt 16 and pivotally connected at its uppe end tothe chassis 2 by a bolt 17. At each end of the shaft 1 there is a roller18 secured by pins 19 to the shaft in longitudinal alignment with oneofan interconnected pair of driven wheels of the vehicle. The peripheralsurface of each roller is concave and is shaped to engage a peripheralportion of the tyre of the said wheel. The concave peripheral surface ofeach roller 18 may have longitudinallyextending ribs thereon to improvethe engagement of the roller with the tyre. As each sleeve 5 is turned,the bearing blocks 3 and hence the shaft 1 will be swung in an are aboutthe axis of the pivot bolt 17 and so each roller 18 will be moved intoand out of engagement with the tyre of the adjacent driven wheel of thevehicle. FIGURE 1 shows a roller 18 in its operative positions in whichit engages the tyre of one of a pair of driven wheels 2%. The otherroller 18 is not shown but in the illustrated position it is also inengagement with the other wheel 20.

Under normal road conditions, the rollers 18 are in their inoperativepositions in which they are spaced from the periphery of the tyres ofthe driven wheels 29; but if ground conditions are such that one of thedriven wheels loses its adhesion with the ground and the vehicle isunable to be moved by the normal differential gear drive of the vehicle,the sleeves 5 are turned to bring the rollers 18 into engagement withthe driving wheels, thereby directly coupling the slipping wheel throughthe shaft 1 to the other wheel of the pair, which is on firmer ground,thereby enabling the vehicle to move. When the vehicle has moved on tofirmer ground and the slipping has stopped, the rollers 18 are retractedfrom the wheels by turning the sleeves 5 in the opposite direction andthe normal transmission through the differential gear drive then takesplace.

Other means for supporting the bearing blocks 3 from the chassis 2 maybeemployed. For example, the .pair

of links at each side of the vehicle may be replaced by a bell cranklever pivoted to the chassis, one arm of the lever being attached to therelevant bearing block .3 and 'the'other arm being connected tooperating means. Alternatively, the links of adjustable length, in theillustrated example, may be replaced by links adjustable by means otherthan the sleeve 5, for example the links may'comprise a screw memberengageable in a socket member, the screw member being supported and heldfrom axial movement in a block pivotally mounted on the chassis and thesocket member being pivotally mounted on the bearing block, wherebyrotation of the screw member will alter the distance between the centresof the pivoted mountings. Alternatively, the adjustable links may betelescopic. The bell crank lever, screw, telescopic link or otheroperating member may be actuated by direct oil system, compressed air orvacuum cylinders.

remote controlmeans, Where provided may be interconmanual operation orby remote control, through a mechanical linkage or by fluid-operablemeans responsive to a fluid pressure derived from a pressurisgd T enect'ed to the transmission system of the vehicle, "so that the rollers13 will be moved into and out of engagement automatically, when slip ofa driven wheeltakes'place.

The additional drive mechanisinmay be fitted" during the manufacture ofa vehicle; but as the bearing blocks 3 can be supported at any desiredposition on a vehicle for example said links supporting each block being{of adjustable chassis and,,as in the case of the illustrated example,the:

turnbuckle device provides a link of variable length, the.

additionaldrive mechanism may be used on different makes or types ofvehicle and thus may be fitted to existing vehicles. e 1

The additional drive mechanism may be used with vehicles having pairs ofsingle or multiple driving wheels.

In the latter case a single roller 18 can ,be provided at 7 each endofthe shaft L'the' rollers .18 each being engageable with only one ofthe wheels at each side of the.

chassis, as in FIGURE 1. Alternatively, there may. be

more than one roller at eachend of the shaft ljeach engageable with adiiferent driven wheel, or a longer roller capable of embracingboth orall the driven wheels of the-driven pair of multiple wheels at therespective side ofthe vehicle.

' bearing block, whereby ,rotation'of said screw member"; will alter thedistance-between ,thecentres; of said pivotal] What I claim as myinventionand desire to secure by Letters Patent of the United States is:

1. In a motor vehicle having a pair of laterally-spaced wheels driventhrougha differential gear drive positioned between :them, an additionaldrive mechanism movable into and out of an operative position in whichit positively. couples one of the wheels ofthe pairto the other, the

'mechanism comprising a pair of laterally-spaced rollers to bepositioned one at each'side of the chassis ofthe vehicle for rotationabout a common axis parallel with the common axis of the wheels,arotatable shaft interconnecting said rollers and apair of linkspivotally mounted on each side of said chassis nad carrying'said' shaft,at least one of said links being adjustable in length whereby the shaftand the rollers are movable bodily. into '7 and out of positions inwhich'theywill each engage a pcripheral portion of the adjacent wheelsof said pair thereby to eifect a direct drive through said rollers andsaid shaft from one to the other of said pair of wheels, so that'whenone wheel slips the rollers may be engaged with each of the wheels todrive the slipping Wheel.

'2..A mechanism as claimed in claim 1 in .which'the support means forthe shaft comprises a pair of bearing. blocks supporting said shaft andspaced apart laterally of the chassis and, attached to each block, apair of links. pivotally' attached at adjacent ends to said block andarranged to be pivotally. attached at :their opposite ends to thechassis, one of said links supporting each block being.

of adjustable length, thereby to' eifect swinging :of .the

blocks, the shaft and the rollers bodily into and out of positions inwhich each of said rollers engages the periphery of one of said wheels.

3. A mechanism as claimed in claim 2 in which each said adjustable linkcomprises a. turnbuckle device by which its length is variable. 7

' 4. In a motor vehicle having a pair of laterally-spaced wheels driventhrough a differential gear drive positioned I between them, anadditional drive mechanism movable into and out of. an operativeposition in which it positively couples one of the wheels'of the pairtothe other,

the mechanism comprising a pair of laterally-spaced rolllength, therebyto effect swinging of theiblocks,the'shaft' H V and therollersbodilyintoand. out of'positionsinj which;

each of said roller'sengages the periphery ofone of'said be engaged witheach, of the wheels. to drive the slipping wheel, each said:adjustable'link comprising interengaging screw and socket members, saidascrewmemberbeing sup ported by and held from axial movementby said chassisi andsaid socke-tmember being .pivotally rnounted on said mountings. ofeachsaid adjustable linki- '5; A motor vehicleincludingapairoflaterally-spaced wheels, an interconnecting;difierential: gearidriveby which they are" driven, and an additional drive mechanism movableinto and out of'an operative positionin gwhich it positively 'couplesjone of said wheels.to thejother, the mechanism comprising a pair oflaterally-spaced ro1lers.- 7 'positionedone. at each side-of the chassisor the vehicle" for rotation abouta common axis parallel jwithfthecommon axis of the wheels, la' rot'atable shaft-interconnecting saidrollers and a pair of. links; pivotallyimountedon each e side of saidchassis and .carryingsaidshaft,at leastone 1 of said links beingadjustable. in length whereby the; shat-t4 and therollers are movablebodily into and out of positions in which they engage a.periphe'ral-pontion of the..'ad-- jacent wheels of saidpaif,'thereby.to eii e'cta direct drive through said rollersandsaidi'shaftfrom one to the o'therl" of saidpair of whee1s, so ;thatwhen one wheelslipsthe rollers. may be engaged with each ofjzthe. wheelstodrive theslipping Wheel}. 7

6s A vehicle'asclaimed in claim 5 in which the. support means for saidshaft comprises a pairlof' bea ringblocks, supporting said.'shaftifandspaced apartalaterallyf of the; chassis and, attached toTeach said block, apair foflinks j 7 adjacent endssto said 'bl'o'ckandat. 7 their opposite ends to, saidchassisone of said links-supe portingeach said block being ofiadjustahle'length, there-f. by toefiectiswinging of the blocks,.ithe;shaft and thezrollg-k pivotallyattached at ers bodily into and: out. of positions in which each'of saidrollers engages the periphery of one of said wheels.

length is variable;

ReferencesCitedbytheExaminer I 2,944,616 7/ 60 Bernard get ale B NJAM-inreassign-ima Exams-ea f r I 'AQHARRY LEVY, stamina; j

wheels and thereby t'o .efiectadirect drive through said; rollers andsaid shaft from; one to the ,otherof said pairof wheels so that'when oneWheel, .s'lips,-., -therollers may" "7," Avehicle as claimed in claim 5inyvhich each said adjustable linkcomprisesa turnbuckle device by whichits

1. IN A MOTOR VEHICLE HAVING A PAIR OF LATERALLY-SPACED WHEELS DRIVENTHROUGH A DIFFERENTIAL GEAR DRIVE POSITIONED BETWEEN THEM, AN ADDITIONALDRIVE MECHANISM MOVABLE INTO AND OUT OF AN OPERATIVE POSITION IN WHICHIT POSITIVELY COUPLES ONE OF THE WHEELS OF T*HE PAIR TO THE OTHER, THEMECHANISM COMPRISING A PAIR OF LATERALLY-SPACED ROLLERS TO BE POSITIONEDONE AT EACH SIDE OF THE CHASSIS OF THE VEHICLE FOR ROTATION ABOUT ACOMMON AXIS PARALLEL WITH THE COMMON AXIS OF THE WHEELS, A ROTATABLESHAFT INTERCONNECTING SAID ROLLERS AND A PAIR OF LINKS PIVOTALLY MOUNTEDON EACH SIDE OF SAID CHASSIS NAD CARRYING SAID SHAFT, AT LEAST OINE OFSAID LINKS BEING ADJUSTABLE IN LENGTH WHEREBY THE SHAFT AND THE ROLLERSARE MOVABLE BODILY INTO AND OUT OF POSITIONS IN WHICH THEY WILL EACHENGAGE A PERIPHERAL PORTION OF THE ADJACENT WHEELS OF SAID PAIR THEREBYTO EFFECT A DIRECT DRIVE THROUGH SAID ROLLERS AND SAID SHAFT FROM ONE TOTHE OTHER OF SAID PAIR OF WHEELS, SO THAT WHEN ONE WHEEL SLIPS THEROLLERS MAY BE ENGAGED WITH EACH OF THE WHEELS TO DRIVE THE SLIPPINGWHEEL.